Page:1902 Encyclopædia Britannica - Volume 27 - CHI-ELD.pdf/355

 CUTTLE-FISH 319 of 6 per cent. The land revenue and rates were homology of the arms and their relation to the head of the its. 10,32,983; the number of police was 571; the num- Cuttle-fish. The majority of naturalists consider the arms ber of boys at school in 1896-97 was 55,351, being 39’2 to be part of the “foot,” which has grown up so as to per cent, of the male population of school-going age; surround the mouth, because they originate at the same the registered death-rate in 1897 was 33-39 per thousand^ part of the embryo as does the foot of a snail, and are The Orissa canal system, which lies mainly within Cuttack innervated from a ganglion corresponding in its connexions district, irrigated in 1897-98 an area of 200,943 acres, and with the pedal ganglion. In this view the siphon and carried 546,766 tons of cargo. The gross receipts amounted its appendages form the remainder of the foot, and the to Its.5,51,924, showing a net profit of Rs.12,005. The animal is represented, for comparison, as standing with its railway across the district towards Calcutta was opened head downwards and its body obliquely upwards. Others in 1899. Considerable trade is carried on at the mouth of consider the siphon to represent the whole of the foot, and the rivers along the coast, the principal port being near the the arms to be organs special to the class. The origin of lighthouse at False Point. In 1897-98 the value of the arms in the development of the embryo is certainly the exports (mostly rice) was Rs. 25,76,728 for foreign very distinct at first from that of the siphon. and Rs. 1,50,452 for coasting trade. The imports are inThe number of distinct forms now included amongst significant. existing Cuttle-fish is very large, the latest census giving 464 species. These may be described as clustering Cutt9e-fish. — The Cuttle-fish, whose general principally round certain well-known types, as the Recent forms. anatomy has already been described in the 9th edition Octopus or Poulpe, the Sepia or Squid, and the of the Ency. Brit., are classed in the sub-kingdom Loligo or Calamary, with a few specially isolated and Mollusca on account of their bilaterally symmetrical, interesting forms. Of these latter may be enumerated unsegmented bodies, their possession of a fleshy integu- the Cirroteuthis and the Opisthoteuthis, which are finned ment, or “mantle,” and of a muscular “foot,” and the Octopods in which no odontophore has been found, while arrangement of their nervous centres in three pairs of ganglia. They are placed in the cephalous division on account of their having a distinct head, and a buccal cavity lined in almost all cases by a toothed lingual ribbon or “odontophore.” Within this division they are sharply marked off as an anciently developed distinct class by the following characters. In the earliest stage of their growth a part only of the germinal substance of the ovum is segmented, instead of the whole, as is commonly the case in other molluscs. They are provided with strong parrot-like horny jaws surrounded in the Octopods by eight, and in the Decapods by ten, sucker - bearing arms; their brain is encased in cartilage; their eyes are enormous ; and on their ventral side is an ejecting siphon or funnel, at the base of which lies the ink-bag. These characters combine to make them the most active, intelligent, and predaceous of all the marine invertebrates. Fig. 1—The Argonaut in life. (After Lacaze-Duthiers.) Tr, float; Br.a, anterior arms ; The class Cephalopoda, of which the general gf-Py posterior characters are thus indicated, includes as a the beak shell; F,En,thetheexpanded funnel. portion of them, once called the sails; B, distinct group the members of the Pearly Nautilus Order, which differ only in the living animals their arms are webbed together like an umbrella; and the by minor peculiarities, as follows :—They are protected latter has its siphon directed backwards. These are probably by an external camerated shell; their jaws are calcareous retrograde forms. Others are the Argonauta and the and of different form; their arms are in lobes, with Spirula, on which of late years fresh light has been clinging tentacles in place of suckers; their siphon is thrown. . Of the Argonaut many fables have been told as not a complete tube, and there is no ink-bag; their eyes to its position in the shell, and its mode of progression, but have no lens, but only a pin-hole aperture; and they in 1892 Lacaze-Duthiers had an opportunity of watching have four branchiae instead of two, each of which is the living animal for a fortnight (Fig. 1). It forsakes its provided with a sense-organ or osphradium, but there are shell in adverse circumstances, but enters it again under no branchial hearts. These characters indicate a less favourable conditions. The front edge of the shell is active and intelligent animal, and one less removed by then kept nearly vertical, and the early part of the development from the primitive type of the class. The coil, encloses air which serves as a float. The funnel number of the branchiae has been used for the purpose of projects in front below, and the beak above, the eye. nomenclature, so that while the Nautilus Order belongs The broad pair of arms embrace only the hinder part of to the. Tetrabranchiata, the Cuttle-fish Order belongs to the shell, leaving the front part uncovered, and the other the Dibranchiata. Besides these two orders there is an arms in swimming are tucked inside the shell between it immense number of fossil forms, of whose branchiae nothing and the body. is ever likely to be known, and they have accordingly been A.well-preserved specimen of the animal of the Spirula, as sometimes classed as Tetrabranchiates and sometimes as obtained by the Challenger Expedition, has been described Dibranchiates, but they ought rather to be called Ignoto- by Pelseneer. The shell is naked and exposed both on the branchiates. front and back of the animal, and coils towards the ventral Much discussion has taken place as to the true side, on which the siphuncle lies. The mantle sac at first
 * C, thearms;