REPOET ON THE PHYLLOCAPIDA. 



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distinguished by its lamellar structure and peculiar expanded form, the outer edge 

 bulging out as a strong curve, whereas the inner is quite straight. The latter bears a 

 row of short setae, whereas the outer edge is armed with numerous small denticles, 

 arranged pretty regularly in a single series. The inner branch is considerably longer 

 than the outer, but much narrower and lanceolate in form. It is composed of two 

 distinctly defined joints, as in the other genera, the first quite short and bearing inside 

 the usual linguiform lobe, the second evenly tapering 

 to the apex, and all around the edges fringed with 

 ciliated setae. The first pair of pleopoda only differ 

 from the other three by the outer branch being some- 

 what less expanded. The last pair, as in the other 

 genera, are somewhat shorter than the preceding pairs, 

 but otherwise of the very same structure. 



The two pairs of rudimentary caudal limbs suc- 

 ceeding the pleopoda (see fig. 1) are very small, and _# 

 quite alike, forming simple narrow plates, setose at the 

 edges and pointing directly backwards. 



The caudal rami were broken off in the specimen 

 examined, and are only conjecturally indicated in fig. 1 

 by dotted lines. When, however, recently preparing 

 the specimen for retransmission, I detected at the 

 bottom of the tube in which it was originally pre- 

 served, a part, which, in spite of its anomalous 

 appearance, I cannot but believe to be one of the 

 caudal rami, detached from the specimen. In the 

 accompanying cut I give a figure of this part, drawn 

 to the same scale as figs. 3 and 4 on PI. III., which 

 represent limbs from the same specimen. In its 

 general appearance it somewhat resembles the outer 

 branch of the pleopoda, but is very much larger, 

 measuring nearly 5 mm. in length and thus about 

 equalling that of the posterior division of the body, or tail. It has the form of a rather 

 broad lamella, somewhat expanded in the middle and drawn out to a slightly incurved 

 extremity, which is narrowly truncate. The edge, which I regard as the outer, is 

 sharpened and evenly curved, with seven angular notches, to which as many spines may 

 have been affixed, one of which, the most proximal, still remains. The latter is very 

 small, but in all probability the others successively increased in size posteriorly. The 

 inner edge is evenly convex in its proximal part, but becomes slightly sinuous towards 

 the end. It is considerably thickened and exhibits two distinct lips, limiting a narrow 



Fig.- 1. — Caudal ramus of A'cbialopsis lypita. 



