316 Mr. H. J. Carter on Deep-sea 



several good specimens from the locality mentioned, is about 

 to describe it under the name H. birotulata. The locality of 

 Halichomlria ahyssi^ as before stated, is station 65, =345 

 fathoms, north-west of the Shetland Islands. 



Esperia placoides, n. sp. (PI. XTII. fig. 12, and PI. XV. 



fig. 32.) 



General form fir-cone-like, scaly, oblong, almost cylindrical, 

 round at the summit, rising from a stipitate base composed of 

 a hard perspiculiferous stem, which branches upwards into the 

 interior. Colour now yellowish grey. Surface uniformly 

 divided into plates of various sizes and shapes (PI. XIII. 

 fig. 12, a a a), separated from each other by deep grooves 

 (fig. 12, bh)y except at the summit, which is formed of one 

 continuous large scale pierced with many vents ; margin of 

 the scale scarped all round and circumscribing a somewhat 

 convex villous area (fig. 12, a, a) ; grooves between the scales 

 concave, smooth (fig. 12, i) ; structure of the scale spiculous, 

 consisting of a dense layer of small spicules, which project 

 externally, gi^'ing the villous surface (fig. 12,/"), and interlap 

 internally with larger ones, which, in bundles, project into the 

 sponge (fig. 12, ^r), while the two are knit together, textile- 

 like, by a thin transverse layer at their point of contact, thus 

 forming a plate or scale which easily comes oj9f entire ; struc- 

 ture of the groove (fig. 12, k) sarcodic, consisting of obliquely 

 reticulated rugaj whose interstices are pierced by the " pores " 

 so as to form a sieve-like area, like that in Tisiphoma agarici- 

 formis. Pores about 1-lOOOth inch in diameter, situated in the 

 sarcode tympanizing the interstices of the rugge in the grooves 

 (fig. 12, Tc, Z, & V). Vents chiefly on the summit, where they 

 consist of short conical elevations, terminated respectively by 

 an aperture about 3-48ths inch in diameter, sometimes singly, 

 in one or more of the larger scales (fig. 12, c c&m). Internal 

 structure consisting of the spiculiferous stem (fig. 12, d), which, 

 branching out in all directions, supports the sarcode charged 

 with the spicules of the species and traversed by the excretory 

 canal-system, which ends in the vents mentioned. Spicules 

 of two hinds, viz. skeleton- and flesh-spicules. Skeleton- 

 spicule of one form, viz. sub-pinlike, almost acuate, fusi- 

 form, smooth, sharp-pointed and slightly curved, with the 

 obtuse end less in diameter than the centre of the shaft, 60- by 

 1^-1 800th inch (PI. XV. fig. 32). Flesh-spicules of three 

 foi-ms, viz. : — 1, inequianchorate of the common Esiieria form, 

 separate and in rosette-like groups, 18-6000ths inch long, 

 head 7-60O0ths inch long (PI. XIII. fig. 12, «) ; 2, bihamate 



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