192 Vniversitu of California Puhlicafions in Zoology. [Vol.8 



anfractu anteriore sulci transversalis ad extremitatem anticam excurrente, 

 tripartita inclusum, ciliis e sulcis prominentibus. Os terminale. Flagellum 

 unum pone os. Anus .... Ocellus nullus. Partitio ignota. Maricolae. ' ' 



In Stein's (1883) great monograph, the text for which was 

 unfortunately never completed, he notes (p. 12) his observation at 

 Kiel of "Perid. spiniferum CI. Lach., auf welches bereits Diesing 

 eine neue Gatt. Gomjaulax gegriindet hat, die wohl berechtigt ist, 

 aber ganz anders charaeteri.sirt werden muss." The modifica- 

 tions which Stein made were (1) a correct orientation with the 

 pointed end anterior, (2) designation of a narrow area from the 

 proximal end of the girdle to the apex as an extension of the 

 longitudinal furrow, (3) an analysis of the thecal plates in two 

 species, with three apicais (Frontalien), five precingulars (Basa- 

 lien), five postcingulars (Basalien) and two "Endplatten" one 

 of which is the antapical and the other the posterior accessory. 



Later monographers, Biitschli (1885b), Sehiitt (1896), and 

 Paulsen (1908), all follow Stein in his interpretation of an 

 extension of the longitudinal furrow anteriorly to the apex. 

 Biitschli finds six precingulars (in Gonuaulax pohjedra) and later 

 discoveries of new species have necessitated some modifications 

 in the range in form of body and number of apical plates found 

 in the genus. In essential particulars Stein's diagnosis has stood 

 with but minor additions to the present time. 



2. MODIFICATIONS RESULTING FROM NEW DATA 



As a result of my investigations on this genus certain funda- 

 mental modifications are necessary in the generic diagnosis of 

 Gonyaidax. 



(1) The form of the body is exceedingly varied and affords no 

 basis for diagnosis. It ranges from an almost perfectly spherical 

 form such as is seen in G. sphaeroidea, to polyhedral species such 

 as G. polyedra and G. ceratocoroides, and to elongated types such 

 as G. hirostris and G. joUiffci. In the development of spines, we 

 find conditions ranging from the smooth, spine-free G. sphae- 

 roidea to the spinous G. triacantha, and to G. ceratocoroides with 

 its long processes resembling those of Ceratocorys. In like manner 

 no particular type of surface markings is prevalent. The surface 



