396 PROCEEDINGS OF THE ACADEMY OF [Sept., 



THE ANATOMY OF CALIFORNIAN HALI0TID5:.i 

 BY CLAYTON F. PALMER. 



The past few 5^ears have witnessed great additions to our knowledge 

 of the anatomy of mollusks, and in this phylum probably no group has 

 received more attention than the prosobranchs. And it is equally 

 true that Avhile the bibliography relating to this last named division 

 has assumed large proportions the results are often of a conflicting 

 nature. Even the comparatively limited family of the Haliotidoe 

 have received their share of consideration, and unfortunately a pro- 

 portionate amount of confusion as well. It is thus apparent that the 

 anatomy of Haliotis merits more study, especially on account of the 

 position this mollusk occupies among archaic forms. Something over 

 a year ago, while studying in the zoology department of Stanford 

 University, Dr. Harold Heath suggested to me that the anatomj' of 

 Haliotis deserved further investigation. The western coast of North 

 America is the habitat of several species of this mollusk, and two of 

 these are readily procurable from the university. Therefore material 

 was never lacking, and as it was of relatively giant size the following 

 results are Ijelieved to be correct. 



The material consisted of specimens of Haliotis rufescens Swn. and 

 H. cracherodii Leach, the red and black abalone respectively. These 

 were taken of various sizes and were examined both by gross dissection 

 and in section. So far as I know, no anatomical details have ever 

 been published concerning any species of Haliotis foimd in this part of 

 the world. Hence the following may serve to corroborate, to some 

 extent, certain facts relating to the genus, and to correct certain mis- 

 statements as well. 



Upon opening the mantle cavity of Haliotis, one first sees the two 

 well developed ctenidia of the distinct bilamellate type, the left being 

 somewhat the larger. Near their bases and against the ventral wall 

 of the rectum may be seen the papilla-like openings of the right and 

 left ureters (text fig. A. RU, LU) ; the right aperture generally has the 



* The present paper was completed over four years ago, "and was intended to 

 form a division of a more extended work relating to the anatomy of various mol- 

 lusks from the western coast of the United States. Owing to other duties it is 

 impossible to carry out the proposed plan, at least wthin the near future, and 

 the results in tlioir original form are herewith presented. 



