AMPHIPOD GENUS LEPTOCHEIEUS. 577 



The specimens examined were : — 



3 L. 2)ectinattijS, two females and one male, measuring 2-5-3 mm. ; 

 from Guernsey, sent by Canon Norman. 



1 specimen, $ , 4'5 mm., taken by the ' Huxley' in 109 fathoms, 

 during her cruise on the north side of the Bay of Biscay, 1906. 



3 L. dellavallei, cj » 5-6 mm., from the coast of Senegal, from 

 Monsieur Chevreux. 



3 specimens from Breslau University Museum, referred to 

 above. These latter specimens were sent in two bottles with 

 Dr. Grube's original labels still on them. One bottle, marked 

 ^^ Pi'otomedeia pilosa Zadd. $ . Luss. pice. Mundtheile. Grube," 

 contained two tubes, with one specimen in each. One of these, 

 a female almost ready to moult, with a brood of young just 

 hatched, was dissected, and is evidently the specimen from 

 which Grube made his drawings. That this is so can be 

 proved by a comparison of the figures with the dissections : 

 e. g., the shape of the 2nd maxilla in his figure is due to the 

 fact that a portion of the inner plate with most of the 

 feathered bristles had been torn away (cf. (24) pi. x. fig. 2 m\ 

 with fig. 10) ; and again, in the 1st maxilla he notes the , 

 absence of the apical seta, which seta is, however, thei-e, but 

 too completely masked by dirt to be seen, except under a high 

 power. The other tube contained a female 5*5 mm. long. 

 The second bottle was originally marked " Protomedeia 

 hirsutimana Sp. B. $ . Yollst. Luss. pice. Grube,"' but over 

 the "hirsutimana " is written in a difierent ink " pilosa Zadd." 

 and the words " m. Eiern " added, apparently by Grube 

 himself. The tube in this bottle contains a large, brightly- 

 coloured female, the largest specimen I have yet seen. 



The specimens form a most interesting developmental series in 

 the order in which I have arranged them above. Figures 14, 19, 

 ife 23 are taken from a female j^ectinatits 2'75 mm., figs. 1 & 

 13 from a male 2*5 mm. long, Norman's specimens: figs. 3, 16. 

 17, 25, & 28 are from the female specimen described by Grube: 

 the other drawings are from two males, dellavallei, 5*25 and 

 6 mm. respectively, Chevreux's specimens. The jjecUnatus figures 

 are more magnified than the others for the purpose of comparison. 



Description. 



Head not quite so long as peraeon-segments 1 and 2 taken 

 together ; lateral cox^ners not prominent, truncate. 



Eyes almost round, a little drawn out towards the lateral angle; 

 ommatidia few in number, large, with blackish-brown pigment 

 in the centre, outer row not so darkly pigmented. 



Sideplates (figs. 13-16). — The first sideplate, which has been 

 the principal character for separating the two forms pecthiatus 

 and dellavallei, is of exactly the same structure in all the 

 specimens. It is small, and completely hidden by sideplate 2. 



