424 ZOOLOGY. 



madreporic plates, wlietlier one [monoplacid) or more {polyplacid) ; (3) 

 by the uumber of spines bordering the ambulacra, these being in some 

 iiniserial {monacmithida), and in others biserial {diplacanthida)) (4) some 

 have the madreporic plate, with a circlet of spines {echinoplacida), and 

 others are destitute of such {aneehinoplacida) ; (5) some again have 

 "the greater uumber of the intermediate spines on special local modi- 

 tlcations of the integument, which may be known as special plates" 

 {autacantMd), while "others retain the simpler disposition which is seen 

 in A. riihens and most of the better known forms" (typacanthid)', finally 

 (G), the spines of the abactinal surface afford modifications of various 

 values, some being "simple" [simplices), others "rare" {rarisjnnosce), 

 others "blunt" {obtusispinosw), and still others "acute" {acutispinosce). 

 The possession of one or other of these several characteristics is expressi- 

 ble by symbols, viz: 



1 = monacanthid ; 2 — diplacanthid; 3 = polyacanthid; 



m = monoi)lacid ; p = polyplacid f 



e =echiuoplacid; a =anechinoplacid; 



a' = autacanthid; t = typacanthid; s = simplices ; 



r =rarispin{B; r' = retusispiuos8e; c = acutispinosse. 



Further, to distinguish between the Pentactinida and the Heterac- 

 tinida, Professor Bell proposes "to place the formula for the latter 

 under the mathematical sign of a squarp. root: thus, Vlp is sufficient to 

 distinguish A. calamaria as a mouacanthid, polyplacid, heteractinid 

 form." By the use of such symbols Professor Bell has given the prin- 

 cipal distinctive characters of 78 species within less than an octavo 

 page. The Asterias vulgaris of New England, c. g., is diagnosed by the 

 formula, "2 ats, which indicates that it has (1) five rays; (2) is dipla- 

 canthid, or with biserial adambulacral spines"; (3) " anechinoplacid," 

 or destitute of a circlet of spines to the madreporic plate; (4) "typa- 

 canthid," or with the intermediate spines simply disposed and. not 

 arising from special plates; and (5) with the spines of the abactinal sur- 

 face simple. (P. Z. S., 1881, pp. 492-515.) * 



BILATERALIA. 



ENTEROPNEUSTA. 



Metschuikolf (El.). Ueber die systematische Stelliing von Balanoglossus. Zool. Am., 



4. Jahrg., pp. 139-143; 153-157. 

 . Systematic position of Balanoglossus. Journ. E. Microscop, Soc, (2,) v. 1, 



pp. 462-463. 



[An abstract of the precediug.] 



The systematic position of Balanoglossus. 



The remarkable genus Balanoglossus has been reexamined. The 

 earlier naturalists regarded it, in its adult stage, as a worm, and had no 

 susi>iciou that it could have any other relations. What afterwards 



