BARNACLES FROM GULF OF CALIFORNIA — HENRY 369 



and have white horizontal lines. The summits are oblique. The 

 white alae have summits parallel to the basis. Internally the com- 

 partments are ribbed basally. 



The pit below the adductor ridge of the scutum varies in depth. In 

 one scutum the adductor and articular ridges are confluent (pi. 31, fig. 

 15) . The valve is not roughened. 



The spur of the tergum varies both in width and in length. The 

 tergum shows patches of purple both externally and internally. The 

 articular ridge is very prominent and reflexed. 



Pilsbry did not describe the mouth parts and cirri of the specimens 

 from the Gulf of California, but Nilsson-Canteli has figured the in- 

 ternal parts of the specimens from Bonaire. The mouth parts and 

 cirri of the specimens from Sonora differ somewhat from the descrip- 

 tion of Nilsson-Canteli. 



The labrum has two teeth on one side of the notch and three on the 

 other. The lower pair of spines of the maxilla are larger and longer 

 than the other spines and are set on a slight prominence. The fourth 

 and fifth teeth of the mandible are very short and blunt. There are 

 spines between the first and second teeth. 



The posterior ramus of cirrus i is two-thirds the length of the an- 

 terior and has 9 segments. The anterior ramus has 18 segments. 

 Both rami are protuberant. The rami of cirrus ii have 11 and 10 

 segments, strongly protuberant; the anterior ramus is one segment 

 longer than the posterior. The lower segments of cirrus iii have 

 spinules on the distal sutures and teeth on the anterior borders of the 

 segments. The anterior ramus is 3 segments longer than the posterior. 

 Median segments of cirrus vi have 6 pairs of spines and a few fine 

 spinules on the distal borders. The segments of the posterior cirri are 

 very elongate. The penis is very long, at least twice the length of 

 cirrus vi and has a fine dorsal point. 



BALANUS TRIGONUS Darwin 



Localities: Estero de Agiabampo, Sonora. April 11, 1940, on Cal- 

 linectes bcllt'cosus Stimpson ; Coneepeion Bay, Baja California, on 

 Navimda pacifica Sowerb} 7 . 



Genus TETRACLITA Schumacher 



TETRACLITA SQUAMOSA STALACTIFERA forma CONFINIS Pilsbry 



Locality: San Franeisquito Bay. March 31, 1940, on Acmaea ddl- 

 liana Pilsbry, with Ghthctmalus anisopoma Pilsbry. 



