Characteristics of Botryllus scalaris
| Botryllus scalaris | |
| Colony | |
| Shape | flat |
| Thickness (mm) | 1.0-1.5 |
| Arrangement of zooids | ladder |
| Tunic | transparent, gelatinous, soft, |
| Ampullae size (mm: L x W) | 0.8 x 0.16 |
| Formation of colony part including only vascular system | infrequently |
| Color of pigment cells forming pattern on a colony surface | orange, white, purple |
| Pattern by deposited pigment cells | single pattern |
| Zooid | |
| Length (mm) | 1.5 |
| Ground color | yellow or yellowish brown |
| Number of tentacles (Large),(Small),(Minute) | L4, S4 |
| Number of stigmatal rows | 8 |
| Second row of stigmata | incomplete |
| Number of longitudinal vessels | 3 |
| Number of stomach plication | 8-9 |
| Pyloric caecum | large |
| Asexual reproduction | |
| Peribranchial budding | all seasons |
| Number of buds in each zooid | R1, L1 |
| Vascular budding | infrequently |
| Cycle of takeover | 5-6 days |
| Sexual reproduction | |
| Breeding season | Jun-Nov |
| Arrangement of gonads (position of ovary) | anterior to the testis |
| Testis shape & color | rosette, grayish |
| Color of eggs | orange |
| Production of larvae | ovoviviparous |
| Mature egg diameter (µm) | 220 |
| Number of mature eggs | R1-2, L1-2 |
| Brooding organ | no brooding organ |
| Embryo size just before hatching (µm) | - |
| Development to larvae | in 4-5 days |
| Release of larvae | shortly before degeneration of parent zooids |
| Larva | |
| Length (mm) | 1.5 |
| Length of larval trunk (µm) | 400 |
| Number of larval ampullae | 8 |
| Oozooid | |
| Length (µm) | - |
| Number of tentacles | - |
| Number of protostigmata | - |
| Number of stomach plication | - |
| Number of buds | R1 |
| Colony specificity | |
| Present or absent | present |
| Starting stage of allorejection | after vascular fusion |
| Occurrence of subcuticular rejection | no |
| References | Saito et al., 1981a |
| - : not examined |