212 University of California Publications in Zoology. [Vol.8 



Trans- 

 Loeality Date Length diameter 



Oflf San Diego, Calif., June 28, 1904 40 30 



Off San Diego, Calif., Dec. 2, 1904 38 30 



Oflf San Diego, Calif., Dec. 2, 1904 38 35 



Loring, Alaska, Sept. 15, 1905 40 34 



Loring, Alaska, Sept. 15, 1905 _ 45 40 



Claparede and Lachmann 30-40 20-26(?> 



(1858-1859), p. 405, pi.' 20, fig. 4. 



Murray and Whitting 39 33 



(1899), pi. 29, fig. 7a. 



Faure-Fremiet 40 33 



(1908), p. 230, pi. 16, fig. 19. 



Ostenfeld 40-50 32-44 



(1908), pi. 5, figs. 54-58. 



Variation: Quite variable in amount of overhang (1 to 2 

 girdle widths) and displacement of the girdle (2.2-3 girdle 

 widths), number and development of antapieal spines, from 

 none to two main ones with accessory spinules. and in develop- 

 ment of surface markings. 



Comparisons: IMost like G. digitale with which it has been 

 more or less confused and not with certainty always separable 

 from it. In material from the Faeroes. Irish Sea, Naples, and 

 Alaska which I have examined there seem to be fairly constant 

 differences between the two species which, however, are in some 

 eases difficult to apply. 



From G. diegensis it is distinguished at once by its much 

 smaller size, absence of intercalary striae, and its smaller anta- 

 pieal spines. The table below summarizes the imi)ortant points 

 of difference in the three species. 



Species Characters in Spinifcra Group 



Spinifera Digitale Diegensis 

 Length 24-50^ i5-75^ 60-1 OO^a 

 Width 20-3 7/i U-50fi 45-82 

 Antapieal spines 0-2, small 2 (4) 1-3, usually 3 

 Angle made with ma- 

 jor axis by line join- 27°-40° 5°-]8° (26°) 0°-8° (15°) 

 ing ends of girdle 

 Displacement of gir- 

 dle in girdle widths 2.3-3 1.5-2.5 3-5 

 Overhang of girdle 



ends, in girdle widths 1.5-2 0.5-1.25 0-1 



Form of longi- Widens abruptly Not abruptly Not abruptly 



tudinal furrow opposite distal widened widened 



end of girdle 



Apical 4' Not separated Not separated Separated 



