QQ S. I. Smith — Crustaceans of (he Atlantic Coast. 



however, tlie number of teeth varies from three to five above and 

 from two to six beneath, although the extremes of these variations 

 seem to be of rare occurrence, as the accompanying tabular summary 

 of the result of the examination of one hundred and fifty-nine speci- 

 mens shows. 



This result is, perhaps most noticeable for showing the constancy 

 of what seems a very trivial character, for, among all the specimens 

 examined, not one varies more than a single tooth either above or 

 below the most usual number upon the dorsal carina and only two 

 specimens (the last in the table) exceed this amount of variation in 

 the number of teeth in the ventral edge of the rostrum. 



One specimen, not included in the above summary, has the rostrum 

 slightly distorted and bifid at the tijD as seen from above, — a pecu- 

 liarity undoubtedly due to injury, though there is nothing but a 

 slight lateral distortion to indicate such a cause. 



The two spines of thu anterior margin of the carapax are usually 

 both well-developed, but the inferior one (the pterygostomian) is 

 occasionally very minute or even entirely obsolete. This obsolescence 

 was noticed only in adult males, and is apparently an approach to, 

 the usual entire disappearance of the same spines among the old 

 males of Hippolyte polaris. 



The dorsal aculei and terminal spines of the telson appear to be 

 very constant in character and number. Among seventy-five speci- 

 mens examined with reference to the dorsal aculei of the telson, 

 sixty-nine had either four or five pairs, or four upon one side and five 

 upon the other. Of the six remaining, four are young and have less 

 than the normal number for adults, a male 15™™ long and a female 

 16 "5™™ having only three pairs of aculei each, another male 15"'™ and 

 a female 17™"^ having each three on one side and four on the other; 

 while a male 32"'™ long has also less than the normal number, having 

 three on one side and four on the other, and a female 27™'" has more 

 than usual, having five upon one side and six upon the other. Fifty 

 specimens examined with reference to the armament of the tip of 

 the telson all had the normal number of spines, — two slender and 

 ciliated ones in the middle with two stouter ones each side. 



The largest specimens examined were taken in the Bay of Fundy, 

 the largest males being 39™'" long and tlie largest females 50™™. 



The only specimens I have seen carrying eggs were collected at 

 Eastport, Maine, in April, 1876, by Messrs. Merriara and Wilson. 

 Among over a hundred adult females taken from July to late in 

 October, none were carrying eggs. 



