.>i) MR. G. S. BRADY'S MONOGRAPH OF 



from which a single ridge runs forward, gradually merging in the flattened encircli 



o 



flange of the .interior border. Seen from the front, the shell is sub quadrangular, the 

 ides convex, but flattened, the dorsum forming a flattened arch; the ventral border 

 perfectly Hat, and hounded by the projections of the outermost ventral ridges; the inner 

 ridges form also conspicuous projections, w r hich run obliquely upwards and inwards 

 towards the flattened anterior flange. Lucid spots about six, oolong and irregularly 

 placed, their long diameters pointing transversely across the valve. Surface of the shell 

 smooth and shining, marked by fine impressed lines, forming a pattern similar to the 

 imbrication of fish-scales. Colour pale greenish or white, transparent, with large and 

 irregularly spread patches of deep olive-green or black. 



Female. — Sul quadrangular. Anterior border flattened, flanged, forming with the 

 ventral margin a well-marked angle; rounded above. Dorsal margin boldly arched, 

 highest at the posterior third, whence it sweeps round with a deep curve to the postero- 

 ventral angle. Ventral margin straight, slightly rising behind, and terminating in a 

 flattened squamous plate, which projects backwards, with the appearance of a spine. The 

 other aspects are similar to those of the male shell, except that the ventral surface of the 

 left valve has at the posterior extremity of its contact margin a flattened squamous 

 plate (fig. 67;), which is received into a corresponding depression of the opposite valve. 



The mandibles have a structure similar to those of other Cyprida? ; but the branchial 

 appendage rises from the lower instead of the upper border of the palp* (Plate XXXVII. 

 fig. 3 c). The second pair of jaws have no branchial appendage. In the female (fig. 3e) 

 they possess a large subcorneal palp, which terminates in two seta*. In the male they are 

 pediform ; the last joint of the right side (fig. 3 e") is much elongated, and terminates in a 

 short seta and a long flexuous claw, which is composed of a strong midrib, with lateral 

 membranous expansions; the left jaw has its last joint (fig. SO shorter and wider, its 

 inner margin having two strongly marked angles, one a little above the middle, the 



other near the lower extremity; the outer margin is flexuous, and is produced laterally 

 near its distal extremity into an acutely angular projection; the terminal claw is 

 falciform : the penultimate joint of both sides bears at its apex a dense tuft of short 

 set >. The first foot in both sexes terminates in three curved claws, the central one 

 being much the strongest and longest (fig. 3/',/"). The second foot is slender and 

 curved upward, like that of Ct/pris, terminating in three equal seta?, the second and 



also S iyin D off each a long apical seta (fig. Sg). The "glandula mucosa," 



or testis of the male, consists of a central cylinder, closely beset with radiating filaments 



(fig. 3/), arranged in 50-60 transverse rows, the whole organ being imbedded in a sort 



of glairy matrix. The two glands are connected each by an efferent duct with the 



bnrsa copulatrixr an organ of very complicated structure (fig. 3*), and consisting 



joints 



intromittent 



far as I can make out) of a much convoluted canal f ? vesicula seminalis) 



organ or penis, and two hooked appendages. The whole organ is very 

 dense m structure, consisting probably of chitine, deep brown in colour, and, with the 



t 



2lli\*ll h 7 Sh '. thM "? aPPenr " nCe mUSt ariM f ' r ° m dist » fti °". "» P««» of the animal having probably go. 



.\iiniinea seveial animals, and nlwnra uith *k* — _ . ,. 



examined several animals, and always with the same result. 



