DIPHYES. 31 



The latter (fig. 1) is compressed from side to side, and ends superiorly' in a point whose 

 obtuseness or acuteness varies much in different individuals. The anterior contour presents a 

 slight, the posterior, a very marked, convexity. The ridges of the anterior face are more 

 or less strongly serrated, and end below in three inflcxed points. The hydroecial aperture is 

 quadrilateral, and very large in full-grown individuals ; occupying more than two thirds 

 of the antero-posterior diameter of the lower end. Its lateral edges are cut off very obliquely 

 from behind downwards and forwards, and its anterior boundary (1 a) is formed by two very 

 broad, quadrate, overlapping septal plates. 



The hydrcecium extends for about half the length of the organ.^ The somatocyst is narrow 

 and subcylindrical, and does not extend so far as the upper ccecal extremity of the nectosac. 



The latter is long and narrow ; it widens superiorly, and then narrows suddenly into 

 a tubular caecum. The superior third of the distal nectocalyx (fig. \ b, \ c) is elongated into a 

 pointed process, which is completely received within the hydrcecium of the proximal nec- 

 tocalyx. The anterior margin of this process forms an obtuse angle with the anterior margin 

 of the main body of the organ; but the posterior margin passes at a right angle into the 

 truncated inferior half of the anterior end, so as to form a sort of step. The anterior and 

 posterior sides of the inferior two thirds of the organ are nearly parallel ; the anterior contour 

 being nearly straight, while the posterior is a little convex. 



The nectosac is subcylindrical and rounded superiorly, the nectocalycine duct abutting 

 anteriorly a little below its apex. Of the five pointed processes which surround its mouth, three 

 are the ends of the serrated ridges which extend along the posterior face of the organ. 

 The other two correspond with the terminations of the antero-lateral longitudinal ridges, and 

 when viewed from above are seen also to form the margins of a broad, transverse septal 

 plate, which continues backwards the floor of the hydroecial canal (fig. 1 c). 



The latter is bounded laterally and in front by two thin plates, which commence about the 

 middle of the superior process, opposite whose lower part their anterior margins bend inwards, 

 and finally overlap for a short distance.' The inflexed edges next separate for a brief 

 space, so as to leave an oval interval, and then the left again overlaps the right, by a broad 

 inflected process. Inferiorly the latter ends suddenly, and the two plates run parallel for a 

 short distance, to terminate by abruptly truncated inferior edges. 



The hydrophyllium (fig. 1 e) is a delicate and transparent glassy plate — its edges over- 

 lapping both above and below its point of attachment. Its truncated distal margin is pro- 

 duced and acuminated at its angles. 



Length of the superior nectocalyx . . 1 inch. 



Deptli „ „ . -aw 



Thickness „ „ . • ? « 



' In this and all the following descriptions of the species of Calycophoridee it is supposed that 

 the apes of the proximal nectocalyx is directed upwards, and that the side on which the hydrcecium 

 lies is posterior. 



' Eschscholz indeed says, " Cavitate ductus nutritorii ante medium corporis desinente," which is 

 in strictness true; but the difference between the length of the hydrcecium and half the length of the 

 organ is very slight indeed. 



' This overlapping is well figured by Chamisso and Eysenhardt, loc. cit., tab. x.xxii h. 



