290 Messrs. Alder and Hancock on some new and rare 



Cloak a little indented in front, nearly straight at the sides, and 

 slightly ronnded behind : the general colour is black, sprinkled 

 with minute points of brown, but the front part of the cloak cor- 

 responding to the head is huffish fawn-coloured towards the sides, 

 and black in the centre only. On this part are placed two 

 largish eyes, surrounded by a pale ring. Behind the eyes and at 

 the termination of the fawn-coloured part, a curved line of small 

 white spots crosses the cloak, giving the animal the appearance 

 of having the head detached from the back ; but this is in ap- 

 pearance only, the surface of the cloak being continuous. A 

 suboval fawn-coloured patch, also bordered with white spots, 

 terminates the cloak behind. Under the posterior margin of the 

 cloak in the medial line is situated the anus, and close to it on 

 the right side are three small, slightly pinnate branchial plumes, 

 generally projecting a little beyond the cloak. The tail extends 

 about one-fourth the length of the body beyond this, and termi- 

 nates in an obtuse point. Foot yellowish, tinged with brown or 

 black, and with a few opake white spots. It is rounded in front 

 and does not extend so far forward as the cloak : its sides are 

 nearly parallel, broader than the cloak and usually folded up to- 

 wards it. Organs of generation on the right side. 



The head and shoulders are clothed with large vibratile cilia, 

 the action of which could be observed with a powerful pocket- 

 lens : the sides of the foot are also ciliated as well as the back. 

 A regular pulsation was observed through the cloak, confined to 

 a small portion of the back a little in advance of the branchial 

 plumes, — the usual position of the heart, — from which we in- 

 ferred the presence of that organ. The pulsations were fifty to 

 sixty in a minute. As we had the opportunity of examining only 

 one specimen microscopically, we were not able to make out the 

 whole of the internal anatomy. The nervous ganglions had 

 much the general appearance of those of the Nudibranchs ; the 

 eyes had a lens, and were regularly formed ; the auditory capsules 

 were closely attached to the ganglions, and contained one large 

 otolithe each. The tongue was strap-shaped and covered with 

 spines ; and a little behind it was a curious dental apparatus, 

 similar to what is described by M. de Quatrefages in the stomach 

 of his genus Pelta, and apparently constituting a kind of gizzard. 

 It consisted of four portions, each bearing six denticulated teeth. 

 We cannot speak with certainty respecting the biliary organ, 

 though from the manner the creature slipped when pressed 

 between the plates of the compressor, we have little doubt that it 

 possessed a firm and bulky liver. The other viscera were not 

 made out. 



On comparing our animal with the genus Pelta, we find the 

 resemblance of external form so great as almost to amount to 

 identity. The head in that genus, however, is described to have 



