14 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Ophioconis. I only speak of my studies on the subject in order to 

 be able to state that after reading Matsumoto's work I find myself 

 entirely prepared to adopt, in its broad lines, the classification which 

 he proposes. I shall give a short summary of it. 



Matsumoto first of all removes from the genus Ophioconis several 

 species which have all the characters of the genus Ophiolimna, and 

 he assigns to the latter 0. antarctica Lyman, 0. operculata Koehler, 

 O. diastata H. L. Clark, and O. papillata H. L. Clark. Then, on the 

 basis of the development of the spines and the structure of the teeth, 

 he divides the remaining species into two groups, one including those 

 in which the spines are short and appressed to the arms, forming the 

 genus Ophioconis (restricted) , the other including those in which the 

 spines are elongated and not appressed. The latter is again divided 

 into two groups according to whether the teeth are very small, tri- 

 angular, and pointed, or flattened, slender, and transparent. The 

 species of the first group form the new genus Ophiuroconis and those 

 of the second the new genus Ophiurodon. Matsumoto thus leaves in 

 the genus Ophioconis only O. forbesi and O. brevispina. As for 0. 

 indica, this appears to him to be close to the genus Pectinura, though 

 differing from it in a number of characters. 



I am in complete accord with Matsumoto's point of view regarding 

 the necessity of erecting the new genera Ophiuroconis and Ophiu- 

 rodon and the validity of the characters which he attributes to each, 

 as well as in assigning O. antarctica, 0. diastata, and O. papillata to 

 the genus Ophiolimna, but I differ from him regarding the limites of 

 the genus Ophioconis (restricted). Matsumoto characterizes it ex- 

 clusively on the basis of the short, appressed, and hyaline spines, and 

 the covered mouth shields ; but I believe that there is a third char- 

 acter quite as important as the two preceding which should be con- 

 sidered, and that is the form of the teeth. In the first species de- 

 scribed, 0. forbesi, which for a long time remained the only species 

 of the genus Ophioconis, the teeth are slender, transparent, and flat- 

 tened, appearing as a column of broadened lamellae, the free borders 

 of which are more or less denticulate (pi. 81, fig. 1). In the original 

 description of Pectinura forbesi Heller indicated this peculiarity of 

 the teeth which he described as " grosse, rundliche, blattformige 

 Zahne " ('62, p. 422) . This form of the teeth is very remarkable, and 

 it is also found in the species referred by Matsumoto to the genus 

 Ophiurodon. But in O. brevispina the teeth are not at all of this 

 character. I only know this species, which seems to be very rare and 

 appears never to have been rediscovered, from Ludwig's original de- 

 scription. Ludwig did not describe in detail the form of the teeth 

 and did not compare them with those of O. forbesi. He simply says 



