1894.] 



NATURAL SCIENCES OF PHILADELPHIA. 



223 



FURTHER NOTES ON THE EMBRYONIC WHORLS OF THE 



MURICIDiE. 



BY FRANK C. BAKER. 



In 1890 I described iu these Proceedings (pp. 66-72) the em- 

 bryonic whorls of a number of species of this most interesting family; 

 and in the Proceedings of the Rochester Academy of Science (Vol. 1, 

 1891, pp. 129-133) I added several species to those already described. 

 From that time until a few months ago, I was unable to find perfect 

 material in any collection under my charge. Some mouths since, 

 however, I discovered perfect specimens of Murex troscheli and 

 Euplenra caudata, with the nuclei intact. Descriptions of these are 

 given below: — 



Murex troscheli, List-like. (Fig. 1.) 



The nucleus consists of two and a half smooth, glossy, hyaline 

 whorls, gradually increasing in size; a carina begins at the apex and 

 encircles the base of the whorls near the suture below; it terminates 



in the fourth spiral line of the after growth. 

 There is a considerable varix at the junction 

 of the nucleus with the after growth. The 

 whorls succeeding the nucleus are crossed by 

 four spiral, beaded lines; spinose varices be- 

 gin on the fourth whorl. 



The only species whose nucleus approaches 

 that of the present species is Murex pliciferus (Sowb. ), but that is 

 higher in proportion to its width and somewhat ditterently sha[)ed. 

 The number of whorls are the same iu both species. 



It may not be out of place to indicate here the species of which 

 the nuclei have been described and figured. Descriptions of these 

 may be found in the Proceedings spoken of above. The species 

 described are as follows : — 



Fig. 1. 



Murex acolopax, Dillw. 

 " occa, Sowb. 

 " frihulus, Linn. 

 " rertirostrls, Sowb. 



Murex recurvirostris, Sowb. 

 " .iimilis, Sowb. 

 " frijonl, Hidalgo. 

 (■ailleti, Petit. 



