REPORT ON THE TUNICATA. 
127 
Branchial Sac with four rows of Ions; stigmata. 
Dorsal Lamina represented by short languets. 
Alimentary Canal posterior to the branchial sac. Stomach ovate, smooth- walled. 
Reproductive Organs placed on the right side of the intestinal loop. The ova 
develop in an incubatory pouch formed as a diverticulum from the atrial 
cavity. The larva is of large size, and is gemmiparous. 
This genus was founded in 1881 by Della Yalle ^ for two species of Compound 
Ascidians from the Mediterranean which he named Distaplia magnilarva and Distaplia 
rosea. He pointed out at the same time that Oscar Schmidt’s Cellulophana p>ileata,‘^ 
which F. E. Schulze had shown in 1877 ® to be not a Sponge but an Ascidian, and 
Kowalevsky’s Didemniuni stylifcrum,* which is certainly not one of the Didemnidse, 
would probably find their proper places in the new genus. 
In external appearance, as Della Yalle pointed out, Distaplia resembles colonies of 
the genus Aplidium, but there the resemblance ends, and its true affinities are with 
Cystodytes and Distoma. It is therefore placed quite correctly by von Drasche in the 
family Distomidse, but it is also allied with his family Chondrostachyidae, being united to 
Chondrostachys and Oxycorynia by the new Challenger genus Colella. 
A new species, Distaplia. luhrica, from the Gulf of Eovigno, was added to the genus 
by von Drasche in 1883, and in the same year I found in the collection of Tunicata 
obtained during the “Porcupine” and “Lightning” expeditions a specimen of Distaplia, 
which in my Report ® upon that collection I referred provisionally to Distaplia rosea, 
Della Yalle. This specimen, which was dredged in Tangier Bay, Morocco, from a depth 
of 35 fathoms, is discussed further on. Finally, in the Challenger collection there occur 
.several small colonies obtained from Station 212, near the Philippine Islands, which 
undoubtedly belong to the genus Distaplia, and closely resemble the specimen from 
Tangier Bay. They do not, however, agree well with any of the previously described 
species. They differ entirely from von Drasche’s Distaplia luhrica in the form of the 
colony, and they differ in certain characters from each of Della Yalle’s species while 
agreeing with each of them in other features. Consequently it is necessary to consider 
these “ Porcupine ” and Challenger specimens as belonging to an independent species, 
which may be regarded as occupying a position between Distaplia magnilarva and 
Distaplia rosea. I have named it Distaplia vcdlii in honour of the founder of the genus. 
The four known species of the genus may be distinguished briefly by the following 
characters : — 
1 Nuove Coiitribiizioni, &c., Roma, 1881. 
2 Spongien des Adriat. Meeres, 18(52. 
® Zeitschr. f. vnss. Zool., Bd. xxix. p. 119. 
* Ueber die Knospung der Ascidien, Archivf. mikrosk. Anat., Bd. x., 1874. 
® Trans. Roy. Soc. Edin., vol. xxxii., part ii., p. 219, 1884. 
