ART. 14 FOSSIL AND EECENT BEYOZOA OANU AND BASSLEE 57 



valve) . The opesium is elongated (therefore the parietal muscles are 

 much developed) . The avicularia are very small, constant, placed in 

 all the interzooecial angles, and have the form of small tear drops. 



Genotype. — Dacryonella odonaria Canu and Bassler, 1917. Recent 

 genotype, Dacryonella typica new species. 



Range. — Cretaceous (Santonian) — Recent. 



Structure. — In 1920 we pointed out the morphologic characters of 

 this genus based on a fossil species found in the Eocene (Jacksonian) . 

 The study of recent specimens has entirely confirmed our deductions 

 and we have no changes to make. However, it is preferable to accept 

 for a second genotype a recent species from the Gulf of Mexico which 

 will always be easy to |)rocure for further study relative to the anat- 

 omy or to the larval system. We have discovered four other recent 

 species in the Philippines. — Dacryonella ogivalina, D. papillata, D. 

 trapezoides, and D. suhvespertilio. 



Up to the present this is a tropical genus. The presence in the 

 European Cretaceous (Santonian) of the island of Riigen indicates 

 the warmth of the Cretaceous seas of Europe and how important for 

 the paleontologist is the study of the recent equatorial faunas. 



DACRYONELLA TYPICA, new species 



Plate 5, Figures 4-S; Plate 32, Figures 11, 12; text Figure 8a 



Description. — The zoarium encrusts other bryozoa, hydrocorallines, 



corals, serpulae, and nullipores. The zooecia are distinct, separated 



by an elongated furrow, pyriform; the mural rim is thin, salient, 



much attenuated in the proximal part of the zooecium; the crypto- 



cyst is smooth, shallow, somewhat convex. The opesium is elongated, 



pyriform, limited by the mural rim; the proximal border is more or 



less convex. The ovicell is small, endozooecial, convex, smooth. 



The small interzooecial avicularia are thin, elongated, triangular, very 



constant. 



,, . r\ ' [^0 = 0.20 mm. 



Measurements. — Opesmmi, ^^^ 



^ Uo = 0.15 mm. 



rj . 1X2 = 0.45 mm. 

 Zooeciai, _ _^ 



U2 = 0.30 mm. 



Variations. — Our measurements are average for the variations are 

 so great on the same colony that it is impossible to give them accu- 

 rately. The species of this genus are, moreover, quite variable; it is 

 very difficult to differentiate those with nearly similar measurements, 

 and one must have several specimens to make an exact determination. 

 The ancestrular zooecia have a small opesium with a large crypto- 

 cyst; the marginal zooecia have a very large opesium and a small 

 cryptocyst. 



Structure. — The lateral indentations of the opesium appear to indi- 

 cate the place of the opesiular muscles, but we have not been able to 



