816 BULLETIN OF THE 



1 1. Descriptions of New Genera and Species, with Critical Remarks. 



Here follow descriptions of seven new genera and twenty-one new 

 species. There were, besides, two specimens of Ophiothrix, brought 

 up from 110 and 20G fathoms. The one had the disk completely hid- 

 den by little thorny stumps, showing only the points of the radial 

 shields ; the arm-spines were long, slim, and very jagged ; the other 

 specimen had a small, compact disk, with naked radial shields spotted 

 with green, and green cross lines on the arms; in the centre of the disk, 

 spines ; arm-spines short and very jagged. Both were young, and I 

 did not choose to add to the present complication of this difficult genus 

 by describing them. The Ophiothrix violacea displays certain varia- 

 tions at a depth that are not seen in shallows, but I believe the species 

 is the same. There also were two species of Arnphiura, probably new, 

 bat too imperfect to describe ; and one soft-bodied little thing that may 

 be the young of Ophiomitra, or may be new. 



OPHIURID^I. 



Ophioglypha acervata Lyman, sp. nov. 



Special Marks. — Three arm-spines of unequal lengths ; the middle one 

 commonly shortest ; towards the tip of the arm the spines are longer as 

 compared with the side arm-plates. Under arm-plates with a peak or 

 point without. Those papilla; of the " arm-comb," which are beneath the 

 disk, are flat and square, so as to form an even close-set row. 



Description of a Specimen. — Diameter of disk 9 mm. Length of arm 

 (broken) about 40 mm.* Mouth papilla; seven to each angle, of which the 

 innermost is central, lying just below the teeth, and of similar form, so 

 that it might as properly be considered a true too t th ; the mouth-papilla on 

 each side is of the same shape, but the two outer ones are flattened, angu- 

 lar, much wider than long, with a cutting edge re-enteringly curved, or 

 notched. Teeth three, four, or even five, shaped like a blunt spear-head, 

 swelling in the middle, and rounded. Mouth-shields as long as broad ; 

 broader without than within ; outer side cleanly curved, irmer side making 

 an angle; length to breadth 1.8 : 1.8. Side mouth-shields narrow, and of 

 equal width, meeting within, and thence running along the inner angle of 

 the mouth-shield to the head of the genital slit. First under arm-plate as 



* The arm is doubtless much longer than this, usually. In some smaller specimens 

 it ran out in a thread-like way, something after the manner of 0. robusta. 



