CRUSTACEANS 



they are here omitted for want of a recent opportunity for comparison.' l He explains that the 

 English title of ' Opossum shrimps ' applied to Schizopods is due to their ' habit of carrying the 

 eggs in a receptacle under the thorax until they are hatched, as in the analogous genus of Quadrupeds, 

 the Opossum tribe.' This connexion of the eggs with the peraeon or thorax, instead of with the 

 pleon or abdomen, is normal in the sessile-eyed Malacostraca. Cocks records M. spinulosus ' In 

 ponds, Bar point, Gwyllyn-vase, Swan pool, Helford, Bream Bay, Pendower, St. Ives ; not 

 uncommon.' Bate records the same species as M. chameleon, Bell having earlier identified it with 

 Vaughan Thompson's M. chamaeleon. But these names of this very common species have to yield to 

 the earlier Praunus flexuoms (O. F. Mailer). Concerning M. griffithnae, Bell, Bate remarks : 'We 

 have taken this supposed species, but I feel assured that it is only the younger stage of a macrurous 

 form, probably Palaemon or Crangon, the young of either genus of which it closely approximates.' 3 

 This hypothesis, however, must be dismissed as highly improbable, and at any rate it has hitherto 

 met with no adherents. The species in question has rather been considered equivalent to Siriella 

 armata (Milne-Edwards), and for this the correct name will be S. rostrata (Guerin) if Bell and 

 Norman are right in supposing Guerin's figure to represent Milne-Edwards's species. 3 



In 1856 R. Q. Couch described from Mount's Bay two species, Mysit oberon and Mysis 

 lamornae* The latter of these is now referred to the genus Hemimysis (Sars), distinguished from 

 Siriella by having the apex of the telson cleft instead of entire. The species is pellucid, but having 

 the carapace bright red or orange, and some other parts flecked with the same colour. It is recorded 

 from Falmouth also by Dr. Norman, who in his otherwise very complete revision of the British 

 Schizopoda does not take notice of M. oberon. Couch describes this as having the rostrum bluntly 

 triangular, reaching as far as the circumference of the cornea, the telson lanceolate, rounded at the 

 apex, the rounded portion with two diverging teeth ; ' a perfectly transparent species, the large black 

 eyes being the chief points by which it can be detected.' It must certainly, I think, be a Siriella, 

 and but for the bluntness imputed to the rostrum might be regarded as anticipating S. jaltemis, 

 Czerniavski. 



Norman records Macropsis dabberl (van Beneden) from Falmouth on the authority of 

 Mr. G. C. Bourne. 6 This is a very interesting species, first described and figured by Slabber in 

 1769 as a shrimp with trumpet-like eyes, 6 but without any Latin designation. Like M. oberon it 

 is pellucid as water, but the rostrum does not nearly reach the cornea of the exceedingly elongate 

 eye-stalks. The telson is short, triangular, with rounded apex, and a tooth at each side where the 

 rounding begins. It is rather singular that White, 7 who quotes from Couch's description of 

 M. oberon, also mentions another translucent form as ' Mysis n. s, Plate IX, fig. 4, found, 

 Falmouth (rock pools at), Rev. A. Norman, April, 1855.' Norman himself makes no reference to 

 the brief description and undecipherable figure of this unnamed species. He on his own part reports 

 that Neomysis vulgaris (Vaughan Thompson) is ' found all round our coast in brackish water at 

 mouths of rivers, estuaries, salt marshes, and such-like places,' 8 so that we may safely add it to the 

 fauna of Cornwall. Its genus is distinguished by a long subulate antennal scale and an elongate 

 telson with entire pointed apex. In Schistomysis (Norman), the antennal scale is sub-rhomboidal, 

 with the apex much produced beyond the lateral tooth. Two species of this genus, S. spiritus, 

 Norman, 9 and S. arenosa (Sars) 10 are reported by Garstang from Whitsand Bay, and from the same 

 locality Gastrosaccus sanctus (van Beneden). 11 Gastrosaccus being a preoccupied name, the last species 

 must now be called Acanthocarh sancta. 



The Stomatopoda, as now restricted to the single family of the Squillidae, have the last three 

 pairs of legs two-branched. In other respects they are very unlike the Schizopoda, with which they 

 were for a long time rather absurdly combined. Couch mentions Squilla desmarestii, Risso, as 

 rare, 12 and Bell adds S. mantis, Rondelet, 13 ending his description with the remask : ' Mr. Couch, to 

 whom I am indebted for the specimen above referred to, informs me that the Squillae were brought 

 from the distance of about a couple of leagues, where the bottom is rocky, with some spots of sand.' 

 In this species the great prehensile claw formed by the second maxilliped has six teeth on the finger 

 and the pleon has eight carinae or crests, while the smaller S. desmarestii has only five teeth on the 

 clasping finger and its pleon is smooth along the middle of the back, being content on its first five 



1 Fauna, pp. 80, 8 1. * 'Revision,' p. 40. 



'Compare Norman, Ann. Nat. Hist. (1892), Ser. 6, vol. x, pp. 151, 263, and Guerin's Iconographit, 

 Crustaces, PI. XXIII, fig. 2 ; Explication, pp. 1 6, 17 (the plate being earlier, the explanation later than 1837, 

 the date of S. armata). 



4 Zoologist, vol. xiv, pp. 5284, 5286. 



5 Ann. Nat. Hist. (1892), Ser. 6, vol. x, 250. 



' Naturkundige ferlustigingen, p. 136, PI. XV, figs. 3, 4. 



' Pop. Hist. Brit. Crust, p. 145. * Ann. Nat. Hist. Ser. 6, vol. x, 262. 



' Journ. Mar. Sin/. Assoc. (1891-92), vol. ii, N.S. 331. 



10 Ibid. (1893-95), vol. iii, 221. " Ibid. vol. ii, 331. 



" Fauna, p. 8 i. B Brit. Stalk-eyed Crustacea, p. 353. 



I 2 73 35 



