118 PROF. OWEN ON A NEW SPECIES OF EUPLECTELLA 



The present species (PI. XXI. fig. 1) is six inches in length, two inches across the base, 

 whence the cylindi'oid body gradually expands to near the middle of its length, where it 

 presents a diameter of two inches seven lines, and then decreases to the truncated apex, 

 which is about one inch and a quarter in diameter ; but part of this appears to have been 

 torn away. Thus the form of the body is ventricose, not regularly conical as in Euplectella 

 Aspergillum ; it more resembles a cucumber than the shell after which the first species 

 was named, whence the present species may be named Euplectella Cuctimer. 



The next difference which striies the eye is the absence of the oblique and wavy crests 

 or ridges which project from the network of the cone, and especially the absence of that 

 marginal plate which divides the reticulate terminal cap or lid from the waU of the 

 cylinder, standing out like a ruff or frill in Euplectella Aspergillmn. 



The convex reticulate lid or cap in Euplectella Cucumer (PI. XXI. fig. 3) is bounded 

 simply by the marginal ridge (figs. 1 & 3, r), which represents the last or lowest* of the 

 transverse fibres, but which is thickened by an accession of the constituent fibrils, especially 

 from the oblique series, so as to project slightly like a rim or ' bead ' in carpentry. Some 

 slightly projecting fibrils from the track of the oblique series of fibres, chiefly multiradiate, 

 and of the kind figured in PL XXI. fig. 5, and which scarcely catch the eye, except when 

 in relief at the border of the cylindi-oid, as at^,^j, fig. 1, alone feebly represent the parietal 

 and reticulate crests which so peculiarly distinguish the Euplectella Aspergilliim. In 

 this species the gradual diminution of the cylinder is produced by the convergence and 

 confluence of two contiguous longitudinal fibres at certain parts of the circumference. 

 The like convergence and final interblending of contiguous longitudinal fibres, as they 

 pass from the free towards the fixed end of the body, is also manifested, though in a 

 minor degree, in Euplectella Cucwmer, as at c and e, fig. 1. But the gradual expansion of 

 the cylindroid is made compatible with this diminution in the number of the longitudinal 

 fibres by the divergence of many of the longitudinal fibres as they proceed from the 

 marginal ridge, as at d, fig. 1, towards the widest part of the cylindroid, where their 

 intervals are greater than in the corresponding part of Euplectella Aspergillum. Very 

 few instances of confluence of longitudinal fibres take place before they reach the widest 

 part of Enplectella Cucumer : the majority occur beyond it, as at e, e, fig. 1 ; and besides 

 the diminution in number of the longitudinal fibres, they aU converge as they approach 

 the smaller and attached end of the cylindi'oid. Here the resolution of the several series 

 of fibres into their constituent fibrils seems to take place, at least on one side, viz. that 

 shown in PL XXI. fig. 1, more abruptly than in Euplectella As2}ergillum : on the opposite 

 side, as in fig. 2, the fibres in Euplectella Cuc?imer begin to be resolved into the fibrils or 

 filaments sooner than in Euplectella Aspergillum. The considerably greater length of 

 these fibres appears to offer another marked distinction between the two species : but as 

 the specimen of Euplectella Aspergillum was torn by violence and brought up by the fish- 

 hook from its place of attachment, no safe inference can be drawn as to their original 

 length in that specimen. In the present example of Euplectella Cucumer the delicate 

 separated silky filaments penetrate, and, as it were, permeate, the substance of a mass made 



* On the supposition that the Euplectella hangs dependent from its filamentous attachment. 



