Morse on Living Brachiopods. — Sclutchcrt. 115 
lobe. In Lingula we now know that the neoembryo does not 
pass be3'0nd the two lobed stage, and further that the posterior 
lobe is not the caudal lobe as in Cistclla, Lacaj^cJIa and Terc- 
bratitlina. In Lingula the mantle is not reflexed and the pro- 
tegulum is therefore from the beginning on the outer side of 
the animal. This discovery by Yatsu is seemingly of great 
taxonomic significance. 
Coccal tubules and punctate shells. — Morse states that "a 
very marked characteristic of the Testicardine group is the 
presence, in the shell of many of them, of tubules with which 
the pallium has an organic connection. * * * '•' Preciselv 
what their functions are is still problematical. * * '■' ''■'- 
It has been suggested that they might be respiratory" or "were 
instrumental in conveying growth elements to the shell." In 
the Liiigulidae they may have "functioned as mucous tubes, 
but in these forms only the barest traces of their existence 
have been detected, and in no brachiopod have these pores 
been seen to open externally, at least in the adult form. It 
was long ago established that coecal prolongations of the pal- 
lium project into these tubular perforations of the shell. In all 
cases, at least in the adult, a delicate periosteum covers the 
shell, and conseciuentl}- the tubules do not communicate with 
the exterior. * * * ''•' That the coecal tubules are sensory 
organs of some sort seems highly proliable.'" (pp. 324-325.) 
The punctate nature of the shell in brachiopods is very 
common, and the very fact that these microscopic perforations 
are so abundant in certain families (terebratuloids and stroph 
omenoids ) and absent in many others, shows that whatever 
may have been their function, it was not an essential organ to 
all of them. On the other hand, these ]3erforations are alwavs 
best developed in the outer layers of the shell and may or may 
not be present on the inner layers. This condition of occur- 
rence unmistakaljly indicates that coecal prolongations of the 
pallium where present, is a feature of youth, and is therefore 
most commonly seen in the outermost layer of the shell. Fur- 
ther, that in some forms the tubules functioned throughout 
life over the greater part of the shell, while in other, and ap- 
parently the great majority of cases, they are restricted as 
functional organs to the lateral and anterior margins. To 
make this point clearer I will give a numl)er of cases which 
mav be readilv verified bv others. 
