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 A HISTORY OF CORNWALL about four fathoms of water, on stony ground off Plymouth Sound,' l is no doubt Costa's T. spongicola. This identification, as Bate acknowledges, was made by Norman in 1868. The name Typton, meaning ' the striker,' was given by Costa in allusion to the snapping noise which the creature makes, and which attracted Couch's attention also. This genus has the mandibles without palp, the scale of the second antennae rudimentary, the first legs minutely chelate, the second pair also chelate but large and very unequal. It belongs to the family Pontoniidae. 2 There is, however, still to be mentioned in the Alpheidae the species Athanas nitescens of Leach, who says that it ' is occasionally found in pools left by the tide amongst the rocks on the coasts of Devon and Cornwall.' 3 As it is not mentioned by Couch, Bell infers its rarity in the latter county, he being unaware of the indus- trious researches of Cocks, who reports it ' In ponds, under stones, etc., Gwyllyn-vase, Bar point, Swanpool, etc. ; very common. Var : equally common.' This very small species is distinguished from Alpheus by having a well-developed rostrum, and the eye stalks only partially covered by the carapace. To the family Hippolytidae belong Hippolyte varians, Leach, H. prideauxiana, Leach, and Spirontocaris cranchii (Leach). For the presence of the first in Cornwall we have the authority of Leach, Bell, and Bate, of Couch for the third, and of Cocks for all three. Bate in 1866 and 1878 referred the first to a genus Carad'ma Caridina intended], and added a species which he variously called C. tenuis 4 and C. tenuirostra. 6 Subsequently he restored the former to Hippolyte, of which it is the type species, and apparently relinquished his C. tenuis altogether. Hippolyte Mitchelli, W. Thompson, is mentioned by Adam White as found at Falmouth by Norman. The latter in his Museum Normanianun (1886) makes it a synonym of H. viridis (Otto). The rostrum is toothless above 6 as in H. prideauxiana, with which it may be identical. In the Pandalidae Panda/us montagui, Leach, is mentioned by Couch as the ' long-snouted shrimp,' in evident allusion to its powerful rostrum. Cocks found it in ' trawl refuse, stomach of the Gadus aeglefinus, and Trigla lyra ; rare,' whereas Couch says it is ' common in crab boats,' and adds : ' There appear to be two other species of this minute genus on our coasts, which I have been accustomed to call ' Aesop shrimps,' from their habit of bending up the back into a hump ; but further observation is necessary to decide whether they are known to naturalists.' 7 P. montagui attains a length of 2^ in. or more, so that Couch's intention in speaking of the genus as minute is obscure ; nor is Bell quite accurate in stating that Couch gives the expressive name of ' Aesop shrimp ' to this species in particular. Bate 8 decides that one of the species which the Cornish naturalist forebore to name is Panda/us thompsoni, previously called Hippolyte thompsoni by Bell, and later Pandalus jeffreysii by Bate, then identified with Panda/us brevirostris (Rathke) by Heller, and finally transferred by Caiman to a new genus as Panda/ina brevirostris (Rathke). In the new genus the rostrum is much shorter than the carapace instead of longer. 9 The family Palaemonidae agrees with the Pontoniidae above mentioned, and differs from the Pandalidae by having the ' wrist ' or antepenultimate joint in the second pair of legs not subdivided. It contains that graceful creature, the ' common prawn,' Leander serratus (Pennant), also L. squilla (Linn.), called by Couch the 'Shrimp prawn,' probably on account of its inferior size, and Palaemonetes varians (Leach), capable of living either in fresh water or salt. The last is recorded by Cocks ' In pond near Mr. Symon's timber-yard, Bar ; scarce.' Of the other two species he reports the first as common and the second as not uncommon. The Schizopoda, or cleft-legged crustaceans, have the limbs of the trunk furnished with exopods or outer branches adapted for swimming. The family Euphausiidae, in which the arborescent branchiae are exposed to view, is represented in Cornwall by Nyctiphanes couchii (Bell). Couch, in writing to Bell about this species, says : ' There were myriads in the stomachs of the mackerel at the time when I obtained those which I sent you.' 10 He explains that the fish were taken almost in mid-channel. Bell, in dedicating the species to his friend, does not specify whether he is honouring Jonathan Couch or his son. Bate in 1878 appears to think that the former is intended, and adds on his own account : ' We have since procured specimens near the coast, but only one or two.' ll Norman reports it from ' Polperro, Cornwall, stomachs of mackerel (R. I. [QJ. Couch) ; Cornish coast, 1881 (Dr. Day) ; Polperro (W. Laughrin).' 13 The Mysidae are distinguished from the Euphausiidae by having no true branchiae. Couch is apparently the first to mention their occurrence in Cornwall. He names Mysis spinulosus, Leach, and says : ' There are other species, as well as the nearly allied Genus Cynthia, on our coast ; but 1 ' Revision,' p. 37. ' See Borradaile, Ann. Nat. Hist. (1898), Ser. 7, vol. ii, p. 376. 3 Malac. Podophth. Brit. (1817), text to PL XLIV. 4 Ann. Nat. Hist. (1866), Ser. 3, vol. xvii, 28. 5 'Revision,' p. 38. Pop. Hist. Brit. Crust, p. 120. ' Fauna, p. 79. 8 'Revision,' p. 39. e Ann. Nat. Hist. (1899), Ser. 7, vol. iii, 39. 10 Brit. Stalk-eyed Crustacea, p. 347, on Thysanofoda Couchii. 11 'Revision,' p. 41. ll Ann. Nat. Hist. (1892), Ser. 6, vol. ix, 460. 272