A New Species of Spirontocaris 



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The number of spines on the ventral edges of the abdominal seg- 

 ments varies much; usually there are two on the first, third, fourth and 

 fifth segments, and one on the second and sixth; in about 25% there is 

 only one on the third, in about 5% the fourth also has but one spine, and 

 two specimens were examined where the fifth had only one spine. On 

 the other hand there may be an increase in the number of spines as the 

 fourth and fifth segments sometimes have three spines and in one case 

 the second had two spines on one side but only one on the other. 



Dimensions. — The females varied in length from 65 to 24 mm., and 

 the males from 48 to 29 mm. 



Distribution. — New Brunswick; Bay of Fundy, 'Prince' Sta. 5: Head 

 Harbour, Campobello island: Grand Harbour, Grand Manan. 



Spirontocaris spina (Sowerby). 



Variations. — There is much variation in the form and number of 

 teeth on the rostrum. The rostrum may be concave at its anterior end 

 or pointed depending on the length of the ventral spines. The number 

 of dorsal spines varied from 9 to 33, with an average at 18 to 20. The 

 number of ventral spines varies from 2 to 5. There is a great deal of 

 variation in the size of the dorsal spines especially. There are usually 

 four dorsal carapace spines but occasionally there are five or six. 



The telson usually has four, but sometimes five, lateral spines. The 

 spines on the meri are as follows, the figures indicating numbers of 

 individuals. 



The dactyls of the third to fifth pereiopods show considerable diver- 

 sity of form. They tend to be rather longer and more slender than is 

 typically the case in Spirontocaris and the longer they are the weaker 



