234 PKOCEEDINGS OF THE MALACOLOGICAL SOCIETT. 



It may be observed that tbe alteration in the position of the 

 branchial pocket, though striking, is not morphologically of much 

 importance, and does not imply any considerable modification of the 

 organism. In a flat Dorid the branchiae could hardly be placed under 

 the mantle-edge without undergoing some alteration of structure, 

 but, in a form like the present, where there is space to allow of their 

 being freely suspended, a very slight change in the direction of the 

 intestine and the vascular system is sufl8.cient to account for the 

 difference. 



In any case the present specimen appears to be a special modification 

 of Chromodoris, and not to represent an order parallel to the Crypto- 

 branchiata, as Corambe may be supposed to do. The branchiae, though 

 abnormal in position, have otherwise the characters of the genus 

 Chromodoris, whereas Corambe has merely a few lamellae at the 

 posterior end of the body under the mantle-margin. 



It is also probable that this specimen is not referable to the genus 

 Hypobranckiaia, A. Adams, and it certainly is not his H. fusca (Gen. 

 Rec. Moll., vol. ii, p. 46, and Proc. Zool. Soc, 1847, pp. 23-4), 

 which is a flat brownish animal six inches long. It is very in- 

 adequately described by Adams, but as he places it under the 

 Phyllidiidae, this position, taken in conjunction with his description 

 of the family characters, ought to mean that it has no jaws or radula. 

 He does not, however, say that he examined the buccal parts. In 

 Proc. Zool. Soc. (loc. cit.) he says that Hypobranchicea "differs from 

 all the other genera of the Dorididae in having the vent, and the gills 

 which are extruded from it, situated beneath the edge of the mantle." 

 This language is probably not accurate, but it sounds like an incorrect 

 description of a branchial pocket with pendent extruded plumes like 

 that of Chromodoriddla mirahilis. 



The single specimen is superficially not unlike those of Chromodoris 

 runcinata which were sent with it, but is somewhat slenderer and 

 higher, and resembles Ceratosoma in shape, as the body slopes upwards 

 from the head, and the end of the back is continued above the tail 

 for some distance. The total length from the head to the tip of the 

 tail is 21 mm., from the head to the end of the dorsal surface 16 mm., 

 of the tail 9 mm., of the dorsal process 7 mm. The height at the 

 head is 4"5 mm., at the middle of the back 6 mm., at the end of the 

 back 6-5 mm. The breadth is 6-5 mm. at the head, and 4'5 mm. 

 across the dorsal process. The mantle-edge measures 1 mm. at the 

 sides, and 2 mm. over the head. The texture is soft and flabby. 

 The ground-colour is dirty white, with numerous deep yellow spots 

 and fewer scattered greenish-blue spots. Both kinds are arranged 

 quite irregularly, but they are most numerous on the back, and fewer 

 at the sides. The sole of the foot is colourless. The foot is long and 

 expanded in front, both laterally and anteriorly, so that it projects 

 a considerable distance before the mouth. The anterior margin is 

 thickened, but not grooved. The mantle-margin is thin, quite distinct, 

 and expanded into a small veil over the head. The rhinophores are 

 yellow, stout, and mace-like, with about 15 perfoliations. They 

 are retractile into pockets with hardly raised edges. 



