214 ME. STAKLEY W. KEMP— BISCATAN PLANKTON: 



and very slender, and a large ei)ipod. A small leaf-like extrusion at the base of the 

 epipod may represent the first appearance of a podobranchia. 



The third maxillipedes and first four pereiopods are provided with long setose exopods. 

 The fifth pair are much shorter and possess no exopods. None of the legs show any 

 signs of chelae and the dactyli in all of them are minute. Short pleopods are present in 

 specimens measuring 23 to 25 mm., in a specimen of about 15 mm. they are quite 

 rudimentary. 



Four specimens of this larva measuring from 15 to 25 mm. are present in the 

 collection. Two were caught between 50 fathoms and the surface and two between 100 

 fathoms and the surface (21 d). 



Although in general aspect this larva bears some resemblance to young A. purpurea, 

 the absence of an exopod on the last pereiopod proves there is no close affinity between 

 them. They closely resemble certain of the immature forms described by Spence Bate 

 (Chall. Rep. 1888) under the name of CaricypJms, which have since been considered to 

 be larval Hippolytidse ; it is, however, probable tliat young individuals of several genera 

 are included under this name. 



ANOMUEA. 



A Pagurid metazosea was caught between 100 fathoms and the surface ; the specimen 

 is unfortunately dry. 



Two other Anomurous larvse were caught between 75 fathoms and the surface: 

 numerous specimens of this larva and of some of its later stages have been met with 

 off the Irish coast ; it therefore seems best to defer any account of it until opportunity 

 occurs of dealing viith this more abundant material. 



BRACHYUEA. 



Three metazoaese were caught between 50, 75, and 100 fathoms and the surface and four 

 megalopse occurred at the same depths. 



Additional Note. ' 



Siuce the above was written, a specimen of Acanthephyra debilis, only 10'2 mm. in length, has been 

 found ofl' the W. coast of Ireland. This specimen, which possesses only six pairs of photophores, is very 

 different from that figured by Coutiere as the form in which the species leaves the egg. The rostrum is 

 scarcely longer than the eyes, the pleopods are short and bud-like, no uropods are developed, and the 

 telson is broad, rounded, and apically emarginate, as in young A. purpurea. All the pereiopods are 

 developed, and a bud at the base of each represents the first appearance of a pleurobranch. 



Although the discovery of this specimen shows that the differences between the earliest forms of 

 A. purpurea and A. debilis are less than was previously thought, there is still evidence to show that the 

 A. debilis larva is much the more advanced of the two, for all its pereiopods are formed and the pleopods, 

 although rudimentary, are not totally undeveloped. 



ISejnemher 1907.] 



