short, thick neck. The whole resembles an orcUnary collar-button, the parts of which are regularly 

 or irrecrularly indented around the edges. This form also appears to originate in a simple 

 spindle, each end of which becomes greatly expanded and takes the form of a disc. Later the 

 whole .spindle assumes the form of a double wheel which finally assumes the collar-button 

 shape. This characterizes the genus Bebryce, and will be called the '^ Bcbrycc type" . (See plate 

 XX, fig. 8, «, <5, c and d). 



The eighth form is strictly radiate in its characteristic form ; but, like the others, is 

 derived from the simple spindle. The spindle at first is quite small and sparsely tuberculate. 

 It then becomes slightly curved, and shows a median constricted band. Next, from the convex 

 side of this band two somewhat triangular processes arise, the whole spindle at this stage being 

 somewhat butterfly-shaped, the first, and larger, wings being the two processes just described. 

 After this stage is reached numerous processes branch from the centre and extend on all sides 

 in a radiate manner, finally concealing or obscuring the original spindle so that we have often 

 quite symmetrical stars, double stars, etc. This form is best seen in the genus Hetcrogorgia, 

 and will constitute the ^ Heterogorgia type\ (See plate XXII, figs. 13, 14, 15). 



A ninth form may be designated which is doubtless closely related to the last. Here 

 again the development may be traced back to the simple spindle. This becomes, bent and 

 constricted in the middle as before. From the convex side arises a knob-like process which 

 may lengthen and, with the bent halves of the original spindle, form a triradiate spicule; or, 

 as happens oftener, the knob-like process may divide, in which case it forms the smaller of 

 the four wings of a butterfly-shaped spicule, of which the bent halves of the original spindle 

 form the larger wings. 



When the four wings are nearly of the same size a quadriradiate or cruciform spicule 

 is produced. While these triradiate and quadriradiate spicules are the typical ones of the genus 

 Villogorgia, and form the " Vi/logorgia type\ there arise from the same bent spindles and in 

 the same species, many other forms, often exceedingly complicated (seeplate XXII, figs, i & 2). 

 Indeed, we may find in a single slide of Villogorgia spicules almost all of the types just 

 described belonging to the family Muriceidae. 



A tenth type is found in the regular spindle itself, which, although it may be greatly 

 increased in size and also changed in outline, stifl retains its original terete form with tuberculate 

 processes scattered over its surface; but without branchings, forkings, exfoliations or radiating 

 plates or processes of any kind. (See plate XX, fig. 7^). 



The forms in which the simple terete spindle predominates almost or entirely to the 

 exclusion of all other types are too diversified to admit of being placed in a single genus. 

 It is therefore necessary to break up this unwieldy mass of species by the use of some other 

 character, or characters, in combination with those based on the spicules. 



A useful character for this purpose has already been employed in generic definitions by 

 Verrill^ and Wright and Studer-. The character referred to is the disposition of the spicules 

 so as to be placed en chevron in the calyx walls or over the tentacle bases, the spindles 



' Verrill. Bull. Mus. Comp. Zool., XI, 1883, p. 30. 



ä Wright and Studer. Challenger Report, the Alcyonaria, iS 



