362 Mya arenaria in San Francisco Bay. [May, 
(we may call it Zzgua, not to be confounded with the ligule already 
mentioned). The tip of this lingua is deflected downwards, and 
from its base run backwards two long barbed processes. Over 
the mouth is a similar but simpler structure, called epipharynx, 
and to these the borders of the pharynx are attached, and also 
muscles, If we force open the mouth (by pulling down the 
maxillz), we find the open mouth overarched by epipharynx (con- 
nected with the labrum), floored inwardly by the lingua (or inner 
tongue, formed by the floor of the pharynx), enclosed at the 
sides by the long tendons of the lingua which are stretched up 
like faucial door posts. All these hard parts keep open the soft 
membrane of the pharynx, just as the iron frame of a dredge 
keeps open the netting attached to it. In the upper part of the 
cranial cavity are racemose glands which send down a pair of 
ducts to the inner tongue. The great salivary apparatus of 
the thorax sends forward its ducts which unite and penetrate 
through the basi and medi-labium to the ligule or long outer- 
tongue. 
It would be premature, at the present stage of our knowledge, 
to theorize upon these facts. They indicate a fundamental unity 
of structure of the heads of all insects; but how far and in what 
directions it is varied, and what is its relation to other parts of 
the body, are questions needing further research. 
20; 
MYA ARENARIA IN SAN FRANCISCO BAY. 
BY ROBERT E, C, STEARNS. 
N November, 1874, Dr. W. Newcomb, who at that time resided 
in California, described in the Proceedings of the California 
Academy of Sciences, a species of Mya which had been given to 
him by the well-known collector, Henry Hemphill, who detected 
several specimens of the form on the shore of Alameda county, 
on the eastern side of San Francisco bay. 
The specimens were about two-thirds of the usual average SiZ© 
1 Siebold discovered a triple salivary system in the bee; but the text books tig 
still sadly at variance with each other and with the facts, in their treatment of this 
part of the subject. Some place the bee’s salivary glands in the head, some in the 
thorax, ard some say they are sometimes in one part and sometimes in the other! 
