TOMOPTERIS. 75 



ranean : thus, Tomopteris onisciformis and T. Scolopendra are most 

 probably distinct species. Mr. Gosse's Johnstonella Catharina is, 

 no doubt, a synonym of the latter, since Mr. R. Ball records that 

 Bryarea Scolopendra has been taken in Dublin Bay by Dr. Corrigan 

 (Report Brit. Assoc. 1849, p. 11)"— Gray, Ann. ^Mag. Nat. Hist. 



The Nereis phasma of Dalyell {Poio. Great, ii. 260. pi. 36. f. 16, 

 1 7, & 11) is a second species, apparently, of this singular and beautiful 

 genus. Sir John procured his specimens in the Firth of Forth at 

 Newhaven, and on the Isle of May ; and he thus describes the 

 animal : — "This animal is towards an inch in length. It might be 

 inscribed in a triangle. The head is forked or cleft, furnished with 

 two long antennae issuing from the sides, between the roots of which, 

 or somewhat behind them, are two black eyes, rather oval, and pro- 

 bably compound. If the body is divided into segments, they are 

 invisible from transparence. If so, the segments consist of a central 

 portion, as the central part of the Nereis, and a long arm, an integral 

 part towards each side, gradually shortening from the middle to the 

 lower extremity, which is pointed. Towards this extremity they 

 degenerate into mere stumps, which seem to be successively deve- 

 loped as arms. Sixteen or seventeen of these arms were conspicuous 

 in (one example), and fourteen or fifteen in (another). In some 

 others were four or five or seven pair of limbs or arms. The extre- 

 mity of the limb is cleft, and terminates in two portions like hollow 

 walnut shells. To some of the artists the termination seemed a 

 pencil. An intestinal organ traverses the whole length of the body. 



"This animal is absolutely colourless; it can be distinguished 

 from the water only when in particular positions, and under a par- 

 ticular incidence of the light. It swims horizontally, and then 

 partly by faint undulations. In this position the greater convexity 

 of the back, and slighter convexity of the belly, are sensible. It 

 always seeks the higher part of the water, near the surface, like the 

 Medusae, keeping the antennae recurved. I sometimes believed that 

 segments were indicated on the under surface ; that the whole was 

 crossed by wrinkles which were effaced on extension ; and one of the 

 cleft extremities of the limb also seemed to move as if by a joint ; 

 and the hollows of some contained a minute yellow body like an 

 ovum. The animal is rather of a gelatinous appearance. It can be 

 preserved with difiiculty, from being liable to entangle itself in every 

 foreign substance, and is easily mutilated in its struggles for libera- 

 tion." — Dalyell. 



