Shiflies on marine Ostrarods 229 



different in length; the shorter of these two bristles has rather many fairly long secondary bristles, 

 arranged to some extent in groups, and has short, fine hairs distally; the longer one, like the 

 two short bristles, has short, fine hairs. Second joint: On the proximal half of the anterior side 

 there are fairly numerous bristles: Six or seven more or less long bristles with short, fine hairs, 

 the longest with its point extending somewhat beyond the end joint; the relative lengths of 

 these bristles vary somewhat. Ten or eleven are rather short with fine double pectination 

 (of the type shown in fig. 8 of M. (Cypridinodes) acuminata in this treatise; all these bristles 

 are drawn smooth in the adjoining figure). About five or six bristles, also short but armed 

 with coarse double pectination (of the type shown in fig. 9 of M. (Cypridinodes) acuminata in this 

 treatise; these bristles are furnished with secondary spines in the adjoining figure). All the bristles 

 of the two last categories, the cleaning bristles, are either clearly arranged in two or three rows 

 running steeply and slantingly forwards and upwards or else situated quite irregularly. There 

 is, however, a transition from one type of cleaning bristles to the other. The variability of these 

 bristles was, on the whole, rather striking, one specimen had a cl eaning bristle of the type shown 

 in fig. 6. On the posterior edge this joint has, at about % of the way along it, a single rather 

 short bristle with short and exceedingly fine hairs or bare and a short distance distally of this 

 bristle two more bare bristles situated close to each other, of the same length and strength as 

 each other, somewhat shorter than the former bristle. All the six bristles of the end joint (fig. 5) 

 are smooth. The two middle ones, which are the most powerful, are about a third of the length 

 of the second endopodite joint. Of the two anterior ones the medial one is claw-shaped and 

 somewhat more than half the length of the two middle ones, the lateral one is considerably 

 weaker and also somewhat shorter than the medial one. Both the two posterior bristles are 

 rather weak and different in length from each other, the longest lateral one is slightly shorter 

 than the two middle main claws. Pilosity: The first endopodite joint has dorso-distally a series 

 of short, stiff hairs; on the second endopodite joint there are proximo-anteriorly and along the 

 posterior edge rather sparse transversal rows of exceedingly short, fine hairs; this limb is other- 

 wise bare. 



Maxilla: — Protopodite (fig. 9) : The equipment of the three endites seems 

 to be fairly constant, though slight variations from the type described and reproduced below 

 may be observed, especially in the relative lengths of the bristles. The first endite has nine or 

 ten bristles of moderate length (on all the specimens investigated except one the first number 

 was found). They are several different types: one, situated at about the middle, is powerful 

 but quite short and has only a few distal and rather powerful secondary teeth; one, situated 

 somewhat outside the former, is of the same type as this but rather considerably larger; one, 

 placed somewhat inside these two, differs from the latter bristle only by its having also some long, 

 stiff secondary bristles at the middle; all the other bristles are subequal and somewhat longer 

 than the former ones; the outer one (or if there are ten bristles the two outer ones) have only 

 rather weak distal secondary teeth; the three inner ones have numerous long, stiff secondary 

 bristles, placed extremely close together; of the two remaining bristles, both with a moderate 

 nimiber of long, stiff secondary bristles, one has very powerful, the other rather weak secondary 

 teeth distally. The second endite has six bristles: the two inner ones of these are rather short, 



