119 



but more crowded and less prominent ;^hose near the border 

 with an even, central groove. Ambiil^ra margined with 2-4 

 series of smooth, close, equal spines. Madreporiform tubercle 

 single, lateral. 



The specimen from which the description is taken was brought 

 from Patangaroa, New Zealand. It displays much beauty of 

 form and structure, and probably also during life, of color, and I 

 would, therefore, propose the name of 



S. ELEGANS. 



Dorsal plates arranged somewhat symmetrically, the largest in 

 the centre, and in lines radiating to the arms. Sides of body 

 concave, but not deeply so, of unequal length, one bearing but 

 three marginal plates while the others have four. The promi- 

 nent knobs formed by the four swollen, marginal plates at the 

 extremity of each arm, constitute a striking feature of the spe- 

 cies. The sort of crown shown by each plate, with its border of 

 granules, readily suggests the generic name. 



Specimen not quite four inches in breadth. 



Mr. Ayres stated that in taking a cast in type metal of 

 the specimen described, he had observed a singular pheno- 

 menon. The fused metal having become partially cooled, 

 so as not to run well in the mould, he threw it into cold 

 water ; when the whole mass immediately divided into fusi- 

 form bodies, most of them about J of an inch long, and 

 about two lines thick in the middle. Some of them were 

 a little obtuse, and ragged at one end, and a few were pear- 

 shaped ; but most of them presented the form of two 

 regular cones with quite sharp apices, united by the appo- 

 sition of their bases. The specimens were exhibited to 

 the Society. 



Prof. Wyman stated that in studying the nervous system 

 of the tadpoles of the common Bull-frog, he had noticed an 

 interesting peculiarity in the distribution of the vagus nerve. 

 Van Deen first described in Batrachian Reptiles the exist- 

 ence of a nervus lateralis, similar to that found under the 

 lateral line in fishes ; in addition to this, Prof. Wyman had 



