490 REPORT ox THE OBDEB STOMATOPODA—BIGELOW. vol. xvii. 



tain, however, a few specimens of unusual interest, wliicli will be 

 described in the concluding section of this report. 



As it has not been my intention to expand this report into a mono- 

 graph of the group, I have gone into the matter of classiflcation only 

 so far as seemed necessary to indicate my views as to the relationships 

 of the species with which I have had to deal. I have not used the 

 comparatively recent classification of Gerstaecker (1889), because it does 

 not seem to me at all satisfactory, but have followed Aliers and Brooks, 

 avoiding changes unless there appeared to be strong reasons for making 

 them. In a preliminary paper, however (1893^), I pointed out that 

 the species of the genus Gonodacfylus, as it stood then, fell naturally 

 into two groups, Avhich I ranked provisionally as subgenera, and for 

 one of which I proposed the name Odontodacfylus. It seems better 

 now to regard them as distinct genera, of which one retains the old 

 name, while the other is described in this report under the new name 

 just mentioned. It is possible that the latter will be found on future 

 investigation to merge into the genus Goronida, but they appear to be 

 distinct at present. The genera LeptosquilJa and FterygosqniUa have 

 been inserted in the key to the genera, although there seems to be 

 hardly sufficient ground for separating them from the Chlori delta sec- 

 tion of the genus Squilla. 



A.n analytical key is the best form in which to convey a general idea 

 of the distinguishing characters of a group of species, but it can not 

 always be made to show the natural affinities. Nevertheless I have 

 endeavored to do so as far as possible, and with that end in view have 

 rearranged the species of Lysiosquilla and Squilla. It will be noticed 

 that the principal divisions that I have made in these genera do not 

 correspond with the old divisions into Lysiosquilla and Coronis on the 

 one hand, nor into Squilla and Chloridella on the other. 



This work has almost all been done in the biological laboratory of 

 the Johns Hoi)kins University, and I desire to express my thanks to 

 Prof Brooks for his advice and supervision. I am, however, alone 

 responsible for any errors or omissions that it may contain. I have also 

 to thank Mr. James E. Benedict and Miss Mary J. Rathbun, of the 

 National Museum, for valuable assistance, and Mr. Baldwin for his care 

 in making the greater part of the drawings. 



Order STOMATOPODA. 



This order may be defined as a group of malacostracous Crustacea 

 in which the stalked eyes and the first pair of antennte are borne upon 

 distinct movable segments; the rostrum in the adult is separated by a 

 movable joint from the carapace, which is small and does not cover the 

 last four distinct thoracic segments ; the first five of the eight ])airs of tho- 

 racic limbs arenot biramons and are adapted to serve as accessory mouth 

 parts, the second pair being strongly developed into the large raptorial 



