studies on marine Ostrardds 2S7 



peg. Basale: This has seven ventral bristles, viz: two a-bristles, one b-bristle, two c-bristles 

 and two d-bristles. Of these the a-bristles, the longer of the c-bristles and the d-bristles are of 

 about the same proportions as are shown in pi. XVI, fig. 2, G. S. Bradv, 1897. The b-bristle and 

 the shorter of the two c-bristles, which are not drawn in this figure of BliADV's, are short, the 

 former being about the same length as the a-bristles and distinguished by being displaced to rather 

 a great extent dorsallv; the short c-bristle is almost entirely reduced. The three bristles on the dorsal 

 side of this joint are about as long as these bristles on the above-mentioned figure of G. S. Brady's, 

 i. e. the proximal one, situated somewhat in front of the middle of the joint, generally does not 

 reach with its point the distal boundary of the joint, the two distal bristles are subequal and 

 slightly longer than the proximal one; all three have short hairs or are almost bare. E x o- 

 p o d i t e: This is somewhat longer than the dorsal side of the first endopodite joint. Its two 

 bristles are relatively short, the proximal one of about the length of this branch, the distal one 

 about half this length; both have short hairs. Endopodite (fig. 14): All the four bristles 

 of the first joint have short hairs. The second joint has on its anterior side a sparse series of 

 five moderately long bristles with short and sparse hairs; these bristles differ somewhat in length. 

 In addition this joint has here a rather large number (about 28 — 35) of rather short cleaning bristles, 

 arranged in several more or less irregular rows running oblicjuely upwards and forwards or else 

 almost entirely without any regular arrangement. Most of the cleaning bristles have extremely 

 fine and double pectination (of the type shown in fig. 8 of M. (Cypridi)iodes) acuminata in this 

 treatise; drawn smooth in the adjoining figure); the rest are coarsely pectinated. Posteriorly 

 this joint has four subequal bristles with short, coarse hairs, two next to each other distally, 

 and two, one of them a little proximally of the other, a short distance proximally of the two 

 former ones; the two distal ones are equal in strength. The end joint has seven bristles. Of 

 these the medial-anterior one is rather powerful, claw-shaped, and rather long, generally about 

 half the length of the second endopodite joint. The one situated most posteriorly is very weak 

 and short, as is usually the case in this group of forms; the five remaining ones are subequal, 

 rather weak and short; in most cases about half as long as the main claw. The main claw is 

 bare, the remaining six bristles are more or less pectinated. Pilosity: The first endopodite 

 joint has short hairs dorso-distally, the second endopodite joint has transverse rows of short, 

 stiff hairs along the posterior side. 



Maxilla: — Prot op o d i t e: The first endite (fig. 15) has in mo.st cases twelve 

 powerful bristles of moderate length. Of these the two inner ones are subequal, rather consid- 

 erably longer than the others and furnished with two or three wreaths of rather short, stiff 

 secondary bristles; distally of these they are rather strongly pectinated. The ten outer ones 

 are often subequal; their lengths vary, however, to some extent; most of them have at the 

 middle wreaths of long, stiff secondarv bristles, more copious on the inner ones than on the 

 outer, and distally of these more or less powerful secondary tcetJi. In a rather large number 

 of specimens there was a slight variation from the type shown in the figure to be observed. 

 Outside the outer bristle of those drawn in the figure aii additional bristle may often be found; 

 this thirteenth one is quite short and weakly pectinated. The second endite (fig. 16) has five 

 rather powerful bristles of moderate length, the three outer ones usually somewhat longer than 



